Electrical connector



June l1, 1957 D. w. BRowNE ELECTRICAL CONNECTOR Filed Feb. 2. 1955 s u Y" 1S-N i.. l...- V. I... YAY... r l ont United States Patent iELECTRICAL CONNECTOR Donald W. Browne,Des Plaines,flll., 'asslgnor to Acra Electric Corporation, a corporation of `Illinois Application February z, 19ss,'s`erial-No.-48s,6ss

comme. (cram- 38) This invention relates to an electr-ical connector and, in particular, to a vconnector `for `use withan electrical resistor element.

YIn electricallyheated devices such-as hot water tanks anelectrical heating element sometimes is arranged to extend Vcircumfer-entially around `thetank `or other device to-be heated. To obtain the maximum thermodynamic -etiiciency in heat transfer, it is necessary lthat the heating unit be placed in the closest possible -proximity to the Ytank wall. To this'end, the heating element isgenerally mounted between thin vsheets of heat resistant, insulating material lsuch as mica and the assembly-thereof mounted .in a-fiat, tubular metallic housing. Means for connecting the endsfof thehousing together to draw the entirerassemfblytightly yaround the tank are provided.

To make the necessary electrical connections to the resistor heating unit containedwithin -the housing land .between-the insulating sheets, a connector or terminal .is providedv at each end of the resistor. .In the past, the mounting of this terminal has been-diilicult and costly. Brazing of components of the terminal to the'- metallic housing, .the necessity of accurate alignmentiof the hole made in the outer insulating sheet withrthehole in the `metallic .housing for installing the terminal, the fragile character of the mica causing frequent failure during the hole lproducing operation, diliculty of assembly, and similar manufacturing problems contributed to the high cost.

The principal feature of-my invention is theprovision off anew and improved -electrical connector adapted for simple kand ready installation to an electrical element.

A further feature of the invention is lthe provision of such. a connector which may bereadily and economically installed on a-resistor heater band.

A still further feature is the provision of such va connector having an adapted to allow connection yof a conducting terminal mounted therein to the internally disposed electrical resistor without requiringahole to be made in the insulating sheets and allowing considerable tolerance in the over-all length of such sheets.

-Another feature of the invention is the provision of an electrical connector comprising an insulator bloeit adapted to be secured to the band housing and having a ylateral slot therethrough, Ia flat conductor plate having a first portion adapted to be received vin the housingand Iprovided with means for securing the resistor thereto, a second vportion arranged to be removably inserted -through the insulator block slot and means yfor securing a connecting wire to the second portion.

Other features and advantages of this invention will be 'apparentffrom the following descriptionftakenin 'connection with the accompanying "drawings wherein:

Fig. l isa fragmentary plan View of a resistance heatingband` with a portion broken lawayandemployingthe novel connector` of this invention;

. f insulating bloei; member `fice Fig.j3 is a perspective view, reduced `in size, of the band with lthe electrical connector mounted thereon; and Y lFig. n4 is a fragmentary exploded perspective View of the connector andband assembly.

Referring now `to the drawings, it may be seen that the electrical connector comprises an insulator block 10 removably secured to a portion of a metallic outer housing Ztl, a conductor plate 11 removably secured to the insulating block and tothe end of an electrical resistance unit -21 carried between insulating sheets 22a and 22b in the housing 20, and screw means 12 secured to the block andjarranged to hold a portion of the conductor plate to secure -it yto the insulating block. The specific arrangement kand structure of the assembly will now be described.

The electrical heating band, comprising the metallic housing 20, electrical resistance unit 21 and spaced `insulatingsheets22a and 22b is generally of construction well-known-in theart. The out-er housing 20 includes an `inneryor bottom atmetallic plate 2da-provided with `upstanding edges y26a. In juxtaposition to and disposed outwardly fromvtheinner plate is the inner insulating sheet 22a yextending longitudinally generally the entire length of the inner plate and transversely generally the width of the plate. The electrical resistance unit 21com'prises a reilex resistor mounted on the inner insulating-sheet 22a, extending longitudinally a distance somewhat less than sheet .22a and transversely a distance less than the width of :sheet 22a so that it is completely separated from plate 20a by insulating material. This resistor is 'of a form welbknownin the art generally lconstructed of resistor wire in the size range of #15 to #30 B. & S. gauge and is provided with longitudinally extending end portions 21a. The outer insulating sheet 22!) is placed on the resistor, and extends longitudinally a distance somewhat less than the sheet 22a and somewhat more than the resistor unit 2l. The transverse width of the outer sheet is substantially the same as the width of the inner sheet so that the resistor unit is sandwiched therebetween. An outer or top housing vplate 2Gb, having a length of the order of the circumference of the tank or other member on which the heater band is to be mounted, is placed on the outer insulating sheet 22b. The edges 20a of the inner housing plate are crimped laterally over the outer surface oi' the plate 2Gb holding the assembly of the inner plate, inner insulating sheet, resistor unit, outer insulating sheet, and outer plate together in a flat bandlike conguration. Suitable means 23 are provided to clamp the ends of the outer plate Ztlb tightly together when the band is extended around the tank or member on which it is to be mounted. See, for example, my copending application, Serial No. 290,206, iiled May 27, 1952, now Pat. No. 2,754,406.

To accommodate the electrical connectors, rectangular openings 20c are provided in outer plate Zb, one adjacent each end thereof. The edges of each opening 20c are formed into an upstanding lip 20c having an outwardly directed portion 20c and a laterallyfextending retaining portion 20cm, the lip providing greater structural rigidity to the plate and eifective retention of the insulator block. Preferably, the width of the opening is made as great as possible to allow the greatest bearing surface between the insulator block and the lip 20c', this dimension being limited by the space available between the inturned edges 20a' of the inner housing plate 20a between which the lip laterally extends.

T he insulator block 10 is formed of electrical insulating material and comprises a base 10a-having a recessed portion 10a extending laterally from one side of the base, and an upwardly projecting boss 10b having a lateral cross section somewhat smaller than the base, thereby forming a shoulder 10c therebetween. Extending vertically through the base and boss portions are a transverse through the slot.

aperture orislot d and a centrally positioned cylin-I drical hole 10e. The bottom portion of the hole is provided with an enlarged diameter, thereby forming a nut receiving recess 10e. The outer or top surface of the block preferably is made flat to best engage Vthe conductor platefto ybe described below. The cross section Vof base portion 10a is made slightly smaller than the housing opening 20c so that the block may be received therein with the outwardly extending portion 20c" of the lip restraining lateral movement of the block and lateral portion 20c of the lip retaining the block by its engageing material such as copper and is a generally ilat metal plate having a lirst longitudinally extending portion 11a provided at one end with a plurality of transversely extending slits 11a adapted to receive the end portion 21a of the electrical resistance unit. As best seen in Fig. 2, this portion is adapted to be disposed between the inner insulating sheet 22a and outer insulating sheet 22b so that the energized portion of the connector is electrically insulated from the housing. In assembly, the outer insulating sheet 22h and plate portion 11a are disposed Within the block recess 10a. Extending outwardly from the portion 11a and through insulator block slot 10d is plate portion 11b having cross sectional dimensions comparable to those of the slot to allow ready insertion but to prevent excessive movement therein. An outer end portion 11e` of the conductor plate is provided with a hole 11c and is adapted to be bent at right angles to the outwardly extending portion 11b after the plate is inserted Hole 11C is positioned so as to be in alignment with hole 10e in the insulator block when this portion is bent into juxtaposition with top 10f of the block.

The screw means 12 comprises a binder head screw 12a having its threaded shank portion adapted to be received loosely in the hole 11C and enlargement 10e. A nut 12b is carried in the recess 10e of the block and is held against rotation therein, the nut receiving the threaded end of screw 12a.

' connector plate are placed on the inner insulator sheet 22a which is in turn mounted on the inner or bottom housing plate 20. Outer insulating sheet 22h is then placed over the resistor and connector plate longitudinal portion 11a; the outer insulating sheet being allowed to extend longitudinally to a point between the upright plate portion 11b and the slits 11a. The position of the end of the outer sheet therebetween is not critical as long/as it is bounded outwardly by the insulator block.

Insulator block 10 is next placed on the assembly with the upstanding conductor plate portion 11b received in the slot 10d. Nut 12b which has previously been placed in the recess 10e will be held therein by abutting the outer surface of the outer insulating sheet With the insulator block so mounted. The block base recess 10a has a height comparable to the thickness`clf` the conductor plate and the outer insulating sheet and allows the bottom of the block to Contact the inner insulating sheet, thereby providing complete insulation of the conductor plate between tlreinner and outer insulating sheets and the insulator block. The outer end portion 11C of the conductor assembly Ywith Aits bottom or inner surface contacting the V2,795,685 'i f" outer insulating sheet and the lip 20c engaging the insulator blockvshoulder 10c.A The block boss 10b having the end portion of the conductor plate arranged in l juxtaposition to its outer top surface 10f extends through the opening 20c so that the end portion of the conductor plate will be exposed for connection thereto of a suitable hookup or connectingwire 13. To effect this connection, the screw 12ais inserted through the conductor plate hole 11C and the insulator block hole 10e so as to threadedly engage the nut 12V held in the recess.

The inner housing plate edges 20a are folded inwardly to clamp tightly together the outer plate and the elements contained between the outer platey and the inner plate described above. As the outer plate is held in spaced relation to the inner plate, the 1ip'20c' effectively retains the insulator block 10. Any longitudinal movement of the outer housing plate tending to move the connector assembly when the outer housing plate is clamped by clamp 23 during the assembly of the band on the member to be heated will produce a force which is distributed over the entire width of a side of the lip 20c to move the connector correspondingly. The small movements thus effected are readily accommodated by the reex resistor and as the position of the end of the outer insulating sheet, between the conductor plate and the insulator block, is not critical, this movement will not cause a short in the assembly. Further, as no accurate longitudinal positioning of the insulating sheets is required, manufacture thereof is facilitated; and as no holes are needed in the insulating sheets, breakage and loss are minimized.

The connector may be readily assembled and disassembled or the terminall screw replaced if damaged.

defined in the appended claims.

I claim:

1. An electrical connector of the character described for use with an electrical resistor element mounted in insulating means carried in a housing adapted to be placed under tension, comprising: an insulator element adapted to be mounted in the housing with a portion extending outwardly through the housing; conductor means having a rst portion carried in the insulating means and provided with means for securing the resistor element thereto, and a second portion removably extending outwardly through said insulator element; and securing means associated with said insulator element to hold electrical connecting means and said second portion of the conductor means together in electrical conductive relation.

2. An electrical connector of the character described, comprising: an insulator block having a base and a projecting boss; ya tlat conductor plate having a rst portion extending laterally, exteriorly of the base and provided with means for securing `a iirst electrical element thereto, and a second portion extending through the insulator block; and securing means associated with the block to hold a second electrical element and said second portion together in electrical conductive relation.

3. An electrical connector of the character described for use with an electrical resistor element mounted between insulating sheets within an elongated housing having an opening therein, comprising: an insulator block having a base, a boss thereon having lateral dimensions generally equal to the housing opening dimensions, and a slot through said base and boss, said block base being mounted in the housing with the boss extending outwardly through the housing opening; a conductor having a first portion disposed between the base of the block and an inner surface of an insulating sheet and provided with means for securing the resistor thereto, and a second portion extending through the slot of the block and projecting outwardly from the boss; and securing means associated with the block adjacent said plate second portion to hold an electrical connecting means andthe second portion of said conductor together in electrical conductive relation.

4. An electrical connector of the character described, comprising: an insulator block having a base provided with a bottom portion with a recess in said bottom portion extending from a side of said base, a boss on the base and extending outwardly from a portion of the base spaced from the bottom portion, an aperture extending through the boss and the base and communicating with the recess; ap conductor means having a rst prtion received in the block recess and provided with means for connecting la first electrical element thereto, and a second portion extending through the block aperture and outwardly therefrom; and securing means associated with the block to hold electrical connecting means and the second portion of the conductor means together in electrical conductive relation.

5. An electrical heater band assembly of the character described comprising: an elongated, flat housing including an outer plate having an opening therein, and a spaced inner plate; an inner sheet of insulating material adjacent the inner plate; an electrical resistor element carried on the inner insulating sheet; an outer sheet of insulating material disposed between the resistor element and the outer plate; insulator means having a base disposed outwardly of the inner insulatng sheet and having a lateral recess opening toward :the inner insulating sheet, said base further contacting the outer insulating sheet, a boss projecting outwardly from the base and through the opening in the housing outer plate, a slot extending through the base and the boss and communicating with the base lateral recess; a conductor plate having a first portion received in the lateral recess between the block base and the inner insulating she'et and extending at least partially between the inner `and outer insulating sheets with the resistor element electrically joined to the rst portion of the conductor plate, a second portion extending from the first portion through the slot in the block, and outwardly from the slot; and screw securing means carried by the block to hold electrical connecting means and the second portion of the conductor plate together in electrical conductive relation.

6. An electrical heater band assembly, comprising: a housing provided with a top plate having an opening with an upstanding lip surrounding said opening, and a spaced bottom plate; a iirst sheet of insulating material adjacent the bottom plate; a second sheet of insulating material adjacent the rtop plate; a resistor element carried between the insulating sheets; an insulator block having a base disposed in the housing and abutting said insulating sheets, an upstanding boss carried by the base and having a lateral cross-section smaller than the base to form a shoulder therebetween, said shoulder being in retained engagement with the housing top plate lip with the boss extending outwardly through the housing top plate opening, a slot extending through the base and the boss; a conductor plate having a first portion extending laterally between the block base and the iirst insulating sheet and having means for electrically connecting the resistor element thereto, and a second portion extending through the block slot; and securing means associated with the block to hold electrical connecting means and the second portion of the conductor means together in electrical conductive relation.

References Cited in the le of this patent UNITED STATES PATENTS 1,813,154 Franz July 7, 1931 2,237,151 Knez Apr. 1, 1941 2,452,214 Vogel et a1 Oct. 26, 1948 2,539,628 Kingdom Jan. 30, 1951 

